天然盐藻提取物对小鼠免疫功能影响的研究

目的 研究天然盐藻提取物对小鼠免疫功能有否影响。方法 分别以12.5、25.0、37.5 mg/（kg BW d）3个剂量天然盐藻提取物以玉米油溶解经口灌胃给予小鼠30 d,另设玉米油对照组;于试验的30 d测定小鼠的细胞免疫、体液免疫、单核巨噬细胞、NK细胞活性。结果 天然盐藻提取物能增强小鼠迟发型变态反应和小鼠的淋巴细胞转化能力、能提高小鼠的半数溶血值和小鼠抗体生成细胞数、能提高小鼠单核-巨噬细胞功能和增加NK细胞活性,以上差异均有统计学意义（均P〈0.05）。结论 在一定剂量范围内天然盐藻提取物具有增强免疫力功能作用。     

海藻多糖对肿瘤细胞膜流动性的影响

目的 研究海藻多糖的抗肿瘤作用机制。方法 采用荧光探针DPH法，观察海藻多糖对S180和H22小鼠细胞膜流动性的影响。结果 海藻多糖可升高S180荷瘤小鼠肿瘤细胞的膜流动性，降低H22荷瘤小鼠肿瘤细胞膜流动性。结论 海藻多糖可恢复肿瘤细胞膜流动性至正常细胞膜流动性而达到抗肿瘤的作用。     

褐藻胶新型肠溶软胶丸的研究

研制的褐藻胶新型肠溶软胶丸,在胃中完全不溶,而在小肠中全溶,约79%以上在十二指肠、空肠内崩解。在体外人工肠液中可于5min 内崩解。六年留样观察表明,肠溶性质不变。2～45℃,日光照射或潮湿条件,对胶丸的肠溶效果或药物质量均无影响。     

盐藻提取物对阿霉素诱发小鼠心脏毒性的影响

本文观察β-胡萝卜素和盐藻提取物对减轻阿霉素(ADM)诱发的小鼠心脏毒性的作用。ADM 为单次腹腔内注射,剂量为12mg/kg 或15mg/kg。β-胡萝卜素(0.6mg/kg)、盐藻提取物(0.75mg/kg)和溶剂(0.2ml/每只鼠)在注射 ADM 前24h 腹腔内注射。结果为光镜检查小鼠心肌组织发现,ADM 应用前预先腹腔注射盐藻提取物的小鼠心肌组织中的空泡和 PAS 阳性明显减少。ADM 注射后第4天或35天,单用 ADM 和 ADM 注射前腹腔注射过β-胡萝卜素及溶剂小鼠的心脏湿重均比 ADM 注射前预先腹腔注射盐藻提取物小鼠的明显减轻(P<0.05)。12mg/kg 的 ADM 单次注射以及在注射该量 ADM 前,经盐藻提取物和β-胡萝卜素预先处理小鼠的存活率。在 ADM 注射后的第35天分别是40%、100%和63%。ADM 剂量改为15mg/kg,在ADM 注射后14天.上述分组小鼠的存活率分别是0%、50%和12.5%。有无盐藻提取物预先处理的小鼠存活率之间的差异明显(P<0.05),而预先注射β-胡萝卜素和单用 ADM 小鼠存活率之间的差异无显著性(P>0.05)。这些结果提示,盐藻提取物在对抗 ADM 诱发的致死性心脏毒性上,具有保护作用,而β-胡萝卜素则缺乏保护作用。     

Rapid algal toxicity assay using variable chlorophyll fluorescence for Chlorella kessleri (chlorophyta)

Three methods of algal assays—the standard assay, microassay, and the proposed fluorescence assay—are compared from the point of view of reliability of EC50 detection, the minimum required time for the detection, sensitivity of individual measurement, i.e. at which cell density the particular assay can be used for EC50 estimation, and the time stability of the EC50 values. The assays were performed with green alga Chlorella kessleri strain LARG/1 growing in potassium dichromate solution in Z‐medium ranging from 0.01 to 100 mg Cr L^?1. The inoculation cell density was set according to the standards to 10⁴ cells mL^?1 and according to spectrophotometer/plate reader detection limit. The average EC50 ranged from 0.096 to 0.649 mg Cr L^?1 and there were no significant differences in EC50 between the assay type and the inoculation methods with the exception of the significant difference between EC_c50₇₂ (EC50 established from biomass measured as chlorophyll a concentration after 72 h of cultivation) in the standard assay and EC_r50 (EC50 derived from growth rate) in the microassay in the standard inoculation experiment due to low variability of their values. The EC_f50 (EC50 derived from variable fluorescence measurement) values correspond to EC50 values derived from the growth rates. Fluorescence measurement revealed the toxic effect of the chromium after 24 h of exposure at cell density of 5 × 10⁴ cells mL^?1, less by half than other used assay methods. The positive correlation of EC_f50 and time was found in the standard inoculation experiment but opposite effect was observed at the spectrophotometric one. © 2009 Wiley Periodicals, Inc. Environ Toxicol 25: 554–563, 2010.     

Induction of reactive oxygen species and algal growth inhibition by tritiated water with or without copper

Tritium (³H) is a radioactive element of ecological concern because of its release into aquatic ecosystems from nuclear power plants. However, the acute and chronic effects of tritiated water (HTO) on aquatic organisms are poorly documented, as are its effects on oxidative stress. In addition, the effects of HTO in combination with other contaminants remain largely unexamined. Herein, we document the effect of HTO on a primary aquatic producer (Chlamydomonas reinhardtii) by measuring growth and oxidative stress using fluorimetric (H₂DCF‐DA) determination of Reactive Oxygen Species (ROS) production. The maximum cell density of the alga (1.65 × 10⁶ cells mL^‐1) was reduced by 23% (1.27 × 10⁶ cells mL^‐1) at the highest exposure tested (59 MBq mL^‐1 HTO), whereas cells exposed to 0.9 MBq mL^‐1 showed a significantly enhanced maximum cell density of 1.90 × 10⁶ cells mL^‐1, an increase of 15%. With regard to oxidative stress, exposure to HTO (0.04, 0.16, and 2.8 MBq mL^‐1) induced an early dose‐dependent peak in ROS production after 14–15 min of exposure, followed by a slow decrease in ROS which stabilized after 60 min. Moreover, this study showed that the presence of HTO may influence the impact of other conventional, nonradioactive contaminants, such as copper, a well known oxidizing trace metal for aquatic organisms. A significant synergic effect of copper and HTO on ROS production was observed. This synergic effect on oxidative stress was shown to be linked to an enhanced copper uptake rate measured in the presence of HTO (> 4 times). We conclude that HTO should be considered as a sensitizer when in a mixture with other contaminants, especially through interactions on the antioxidant system of algae. © 2010 Wiley Periodicals, Inc. Environ Toxicol, 2012.     

Screening of Antibacterial and Antifungal Activities of Six Marine Macroalgae from Coasts of Yucatán Peninsula

Abstract

Ethyl acetate partition of methanol extracts of Avrainvillea nigricans. Decaisne (Udoteaceae), Codium decorticatum. (Woodward) Howe (Codiaceae), Halymenia floresia. (Clemente) C. Agardh (Grateloupiaceae), Laurencia obtusa. (Hudson) Lamouroux (Rhodomelaceae), Sargassum filipendula. C. Agardh (Sargassaceae), and Sargassum hystrix. J. Agardh, marine macroalgae from Yucatán peninsula coasts, were screened using the well-diffusion technique against three Gram-positive bacteria, four Gram-negative bacteria, two yeasts, and two molds. The extracts inhibited the growth of Staphyloccocus aureus. at 6.25–1.56 mg/mL and Bacillus subtilis. at 6.25–0.78 mg/mL. Trichophyton mentagrophytes. growth was inhibited by extracts of Laurencia obtusa., Sargassum filipendula., and Sargassum hystrix. at 6.25–3.13 mg/mL. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum fungicidal concentration (MFC) were obtained by the microplate method.     

Antimicrobial Activities of Volatile Components and Various Extracts of Dictyopteris membranaceae. and Cystoseira barbata. from the Coast of Izmir,Turkey

Abstract

The methanol, dichloromethane, hexane, chloroform, and volatile components of Dictyopteris membranaceae. (Stackhouse) Batters (Dictyotaceae) and Cystoseira barbata. (Good et Woodw.) J. Agardh (Cystoseiraceae) were tested for their antimicrobial activities (four Gram-positive bacteria, four Gram-negative bacteria, and Candida albicans. ATCC 10239). Five compounds were identified in the volatile oil of D. membranaceae. accounting for >85% of the composition of the volatile oil. Twenty-eight compounds were identified in the volatile oil of C. barbata. accounting for >67% of the composition of the volatile oil. Major components were 6-butyl-1,4-cycloheptadiene (43.21%) for D. membranaceae. and docosane (7.61%) and tetratriacontane (7.47%) for C. barbata.. Many compounds in the volatile oil of C. barbata. were identified as hydrocarbon compounds. The volatile oils of these algae did not remarkably inhibit the growth of tested microorganisms. However, the hexane extracts showed more potent antimicrobial activity than methanol, dichloromethane, and chloroform extracts.     

Antiplasmodial and antimicrobial activities of South African marine algal extracts

Seventy-eight crude organic fractions from nineteen species of marine algae collected from the coast of South Africa were screened for activity against a chloroquine sensitive strain of Plasmodium falciparum (D10), Staphylococcus aureus, Klebsiella pneumoniae, Mycobacterium aurum and Candida albicans. Fifteen crude fractions showed good antiplasmodical activity (IC₅₀?<10 μg/mL). The dichloromethane fraction from Sargassum heterophyllum (Turner) C. Agardh (Sargassaceae) was the most active with an IC₅₀ value of 2.8 μg/mL. Eleven extracts showed MIC values ≤?1?mg/mL against at least one of S. aureus, K. pneumoniae, M. aurum and C. albicans. The broadest spectrum of antimicrobial activity was exhibited by the aqueous-HP20 fraction of Polysiphonia incompta Harvey (Rhodomelaceae). This study shows that marine algae not only produce antimicrobial compounds but also may be a source of antimalarial lead compounds.